1. Field of the Invention
The present invention relates broadly to the field of solar energy utilization and, more particularly, to an inexpensive, easily fabricated structurally strong, parabolic trough solar concentrating absorber shell.
2. Description of the Prior Art
Rapid depletion of the conventional sources of energy has resulted in a ever widening search for alternatives to such conventional sources as petroleum and natural gas to meet the increasing demand for energy by our society today. One such viable source which is commanding a great deal of attention in research and development and in the deployment of experimental units is, of course, that of solar energy. Solar collectors may be employed, inter alia, as sources of heat for homes and buildings and for maintaining an adequate supply of hot water in such installations.
Generally, the prior art contains many different examples of ways to utilize the solar energy absorbed by concave collector systems in which the raidant energy is reflective from a concave surface onto an absorbing receiver of one variety or another. It is known that a general parabolic-shaped trough will reflect sunlight such that it can be focussed along a line parallel to and above the trough. The location of an absorbing member such as a pipe containing heat transfer fluid along the line of such reflection has been used to heat water or the like in installations of this type.
One example of prior art is contained in a Patent to Parker, U.S. Pat. No. 4,026,273 issued May 31, 1977, which illustrates and describes a solar fluid heater which includes a radiation trap for concentrating solar radiation focussing the solar radiation on the transparent pipe located above the curve of the concentrator and, in turn, heating the fluid in the pipe. An additional reference is contained in a patent to La Vantine, U.S. Pat. No. 3,645,606 issued Feb. 29, 1972, which discloses a light-reflecting concentrator having substantially paraboloidal surface which is formed of a plurality of juxtaposed facets, each facet also having a generally paraboloidal surface. The device is utilized to focus light received on the parabolic surface to a point above the surface where it can be utilized. The invention utilizes two paraboloidal radii on a orthogonal planes in each of said facets and the columnated light can be used as a solar simulator. It is not, however, on the scale of a solar collector.